This invention relates generally to working machine excavators and more particularly to the cab arrangement of an excavator.
The arrangement of an excavator cab is generally constrained by the available space in the forward area of the cab. Generally numerous items are located in this area. These items can include an operator's station, a control console, operator display screens, video monitors, a workstation for service personnel, 2-way or CB radios, and the operator's personal effects. The placement of these items in the forward area must be balanced against many factors, such as providing adequate ingress and egress space for the operator.
When designing an excavator cab, one of the most important features is visibility. This includes visibility of the working part of the machine which includes the bucket, as well as, visibility of the tracks, under carriage, adjacent equipment, personnel, and terrain. Most operator cabs are designed to have one large front window and two side windows to provide visibility of the working part and adjacent equipment, personnel, and terrain. This means that the width of the excavator cab is constrained by the maximum practical width of the front window. Adding a second front window widens the front of the excavator cab, but creates a post that blocks visibility. Placing all machine controls to one side of the operator eliminates visibility on that side.
Issues also arise when training a new operator. Generally, a new operator is trained by being put in control of the working machine while a trainer stands behind the new operator to issue instructions. This puts a relatively untrained operator behind the controls of a very powerful and very expensive piece of equipment. Additionally, the trainer is not always in a position to reach the emergency stop button if necessary.
Depending on the position of the trainer, he or she might not be able to see the working part of the machine, adjacent equipment, nearby personnel, nearby terrain, the operator controls, and the display screens at the same time. Additionally, the trainer will often block the passageways or visibility of the operator. If the working machine encounters rough digging, the trainer will sometimes fall against the new operator.
The idea of locating two operator seats in the front area of the excavator cab has been explored, but it has traditionally been difficult to fit two operator seats, the operator controls, and a passageway within the maximum practical width of the front window.
Therefore, it would be advantageous to have an excavator cab that provides seating for an operator, a trainer, and a trainee which provide a similar line of sight for the operator, trainer, and trainee and can fit two seats, the operator controls, and a passageway within the width of the front window.